Max 401(k) Contributions Calculator

Use this calculator to determine what percentage of your paycheck to contribute to max out your 401(k) contributions by the end of the year.

It calculates both pre-tax/Roth and after-tax contribution percentages and provides a paycheck-by-paycheck schedule.

1The Basics

Birth YearSelect your birth year...1977 – 2026 (under 50)1967 – 1976 (age 50+)1963 – 1966 (age 60-63)1962 or before (age 64+)Age on December 31, 2026 determines catch-up eligibility

Annual SalaryIf you received a raise, use your new salary

Employer Match %100% match up to 4% of pay

ContinueFill in your birth year and salary

2Current Elections

Current Pre-tax/Roth %Your current 401(k) election

Current After-tax %Mega-backdoor Roth eligible

Paychecks In Flight012Number of paychecks using current elections before updates to contribution % take effect

Remaining Pay PeriodsAuto-calculated based on today's date; editable

3Year-to-Date Contributionsfrom your last paycheck

YTD 401k Pre-tax/Roth Contributions

+ Add entry (e.g. prior payroll provider)Total: $0.00

YTD After-tax Contributions

+ Add entry (e.g. prior payroll provider)Total: $0.00

YTD Employer Contributions

+ Add entry (e.g. prior payroll provider)Total: $0.00

▶Advanced Options

Only use this if you have an upcoming bonus that is not already reflected in your YTD contribution totals.

I have an upcoming bonus

How it works

• Calculates optimal pre-tax and after-tax percentages to max out your 401(k)
• Accounts for catch-up contributions if you are 50+ (enhanced for ages 60-63)
• Percentages round up to the nearest 0.5%; the final paycheck adjusts to stay within limits
• In-flight paychecks use your current elections; new rates apply to remaining checks

Terminology

• Elective Deferrals (Pre-tax/Roth): Your direct contributions, subject to the IRS annual limit ($24,500 in 2026, higher with catch-up)
• After-tax Contributions: Additional contributions beyond your deferral limit, up to the overall IRS limit ($72,000 in 2026 base)
• Employer Match: Your employer’s matching contribution counts toward the overall limit but not the deferral limit
• Catch-up Contributions: If you’re 50+ (or 60-63 for enhanced catch-up), you can contribute more

2026 IRS Limits

Age Bracket	Deferral Limit	Overall Limit
Under 50	$24,500	$72,000
50-59 or 64+	$32,500	$80,000
60-63	$35,750	$83,250

Pitfalls to Avoid

• Reaching Overall Limit before Deferral Limit: If you overcontribute to after-tax, you could hit the overall limit before you have a chance to max out your pre-tax/Roth contributions. This may limit the employer match percentage.
• Reaching Deferral Limits before End of Year: If you overcontribute to either pre-tax/Roth combination and max out early, you could miss getting the employer match on the last paycheck(s) of the year. If your company offers a true-up, you will receive the company match but this may push you over the overall limit for the year. Issue snapshot — Consequences to a participant who makes excess deferrals to a 401(k) plan